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  1. CDRIVE

    LED Light Box Troubleshoot

    The benefits of kits like that usually far out way the desire to build from scratch. No scrounging up the components from multiple suppliers. No excessive shipping costs do to multiple suppliers. The kit is typically cheaper than the cost of the individual components. Best of all.... You...
  2. CDRIVE

    please help a supern00b building a 12V timer

    Wow, you are a quick study! I really didn't think I'd check in here today to see that you breadboarded it overnight. Before I became old and decrepit I had that kind of **** and vinegar. :D Anyway, as jackorocko said R2 & C1 (RxC) determines the time period. If you want to vary the timeout at...
  3. CDRIVE

    LED Light Box Troubleshoot

    I doubt that he'll get enough Gate voltage to drive a power MOSFET directly from his IPad's audio. Maybe I'm wrong? ;)
  4. CDRIVE

    LED Light Box Troubleshoot

    OK, I read the sales data the link you posted. They say that their led strips can be cut at every 3 led cut point which they say is about 1" segments. If they're 3 led segments I think the circuit would look like this, which is a series parallel circuit. If anyone is familiar with these strips...
  5. CDRIVE

    LED Light Box Troubleshoot

  6. CDRIVE

    LED Light Box Troubleshoot

  7. CDRIVE

    Need help selecting an Emergency Stop

    Thanks for confirming it's a magnetic contactor (Relay). It's always good to be correct. :D
  8. CDRIVE

    LED Light Box Troubleshoot

    That's because the Internet is rife with bad designs, that are designed by people that know about as much as the people building their stuff. ;)
  9. CDRIVE

    LED Light Box Troubleshoot

  10. CDRIVE

    please help a supern00b building a 12V timer

    Well, where I'm located summer never ends. It's just a matter of blistering hot or Chamber Of Commerce weather. So I here you go. I used a power FET to drive the motor but it can be replaced with an appropriate relay or an NPN Transistor. The current draw of the pump motor shown in the plot...
  11. CDRIVE

    22.2V li-ion battery level indicator?

    The circuit given to you will probably do the job but a comparator would have been the best approach. More complex but not very though.
  12. CDRIVE

    LED Light Box Troubleshoot

    What is the current requirements for that LED strip? Does it have a built in limiting resistor? The TIP31 seems like a lot of overkill to light LEDs unless they are high power. The TIP31 requires a lot of base drive to saturate it as the hFE is only 50 MAX and typically only 35. If this LED...
  13. CDRIVE

    Need help selecting an Emergency Stop

    This statement further reinforces my belief that the E Stop controls a contactor. That is.. unless this machine is powered by an internal combustion engine. Please tell me it isn't.
  14. CDRIVE

    Need help selecting an Emergency Stop

    I'm not sure if this clears things up or not. Are the Start Stop & E Stop momentary push button switches? Posting a photo of your current power panel might help. Most industrial machines are controlled with magnetic contactors. They are much safer than common switches becuause a breif power...
  15. CDRIVE

    Review my circuit

    Ah, not all of them unless they dropped the electromechanical models that they sold. They were rectangular and as I remember 6V. ;)
  16. CDRIVE

    Capacitor Help

    Here's a Spice of a 1000uF cap being charged from a battery. I'm using a 100 Ohm resistor in series with the capacitor because it effects how fast the cap will charge and discharge. I used it primarily because without it the charge and discharge time would be too fast for you to follow on the...
  17. CDRIVE

    Capacitor Help

    joshs, electrons do not flow through a capacitor unless it's leaky. This includes AC current. Instead, the plates of a capacitor charge and discharge, which gives the appearance of current flowing though it.
  18. CDRIVE

    Review my circuit

    I just realized that I think we're all assuming that the buzzer is a Piezo based tone oscillator. If it isn't and is electromechanical you will need a Diode reverse biased across it. Failing to do so will probably pop your transistor. Not needed for a Piezo Buzzer though. ;)
  19. CDRIVE

    Need help selecting an Emergency Stop

    You haven't provided nearly enough information for an intelligent reply. Is the main ON/OFF control a magnetic contactor? Is the Kill switch a NC or NO model? What's the expected max current through the switch, etc.?
  20. CDRIVE

    Review my circuit

    As said, you should move the Piezo buzzer to the collector. Also, I think 220 Ohms for the base bias resistor is much lower than needed but it will depend on what the buzzer draws @ 6V. What's the current spec? BTW, your schematic shows 6V powering the PIC. Is that correct? I'm not used to...
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